ADSORPTIVE VOLTAMMETRIC BEHAVIOR OF THYMINE IN PRESENCE OF GUANINE AT THE STATIC MERCURY DROP ELECTRODE

Abstract

An electrochemical stripping procedure for trace measurements of thymine is described by adsorption on a static mercury drop electrode. Cyclic voltammetry was used to characterize the interfacial and redox behavior. Optimum experimental conditions were found to be the use of a 0.005M NaOH solution, an initial potential of −0.08 V, a scan rate of 100 mV.s⁻¹ and a linear scan mode. The response of free thymine is linear over the concentration range 0.1–0.5 ppm. Linear scan voltammetry, without acumulation time yields a detection limit of 62 ppb thymine. Acridine orange and copper were also investigated for measuring thymine in the presence of guanine.

Keywords:

• Thymine determination
• Guanine
• Acridine orange
• Copper
• ssDNA
• Stripping voltammetry

ACKNOWLEDGMENTS

The authors gratefully acknowledge the CNPq and CAPES of the Government of Brazil for supporting of this work. The experimental assistance of A.B. Neves is appreciated.